/sci/ - Science & Math

>>11312096
I'll reiterate. We assume [math]G[/math] is abelian. We make them move "forward" in the sense given here >>11312075
[math]\chi * \chi '(g) = \displaystyle \Sigma_{hh'=g} \chi(h) \chi'(h'^{-1}) = \Sigma _{hh'=g^{-1}} \chi(h^{-1}) \chi'(h') = \chi'* \chi(g^{-1})[/math]
If you make it stop going backwards, it stops commuting.